This invention relates to methods of treating patients suffering from hearing loss and preventing patients from hearing loss.
Hearing loss and/or hearing impairment may be caused by a wide range of biological and environmental factors. Hearing loss also has a varied and complex etiology. Forms of hearing loss/hearing impairment include acoustic trauma, noise-induced hearing loss, sensorineural hearing loss, mixed hearing loss, unspecified hearing loss, ototoxic hearing loss, drug-induced hearing loss, environmental chemicals-induced hearing loss, cancer-induced hearing loss, surgical-induced hearing loss, radiation-induced hearing loss, infection-induced hearing loss, sudden (idiopathic) hearing loss, auditory processing disorder, and presbycusis.
Noise-induced hearing loss may be caused by acute or chronic conditions. Long-term exposure to excessive noise is the more common cause of noise-induced hearing loss; however, such hearing loss may also be caused by extremely loud sounds.
Sensorineural hearing loss is due to insensitivity of the inner ear or to impairment of function in the auditory nervous system. Sensorineural hearing loss may be caused by abnormalities in the hair cells of the organ of the Corti in the cochlea.
Ototoxic hearing loss may be caused by medications which damage the ear (i.e., drug-induced hearing loss). Such medications include chemotherapeutic (i.e., anti-neoplastics or anti-cancer) agents (such as cisplatin), aminoglycosides (such as gentamicin), diuretics (such as bumetanide), salicylates (such as aspirin), quinines, NSAIDS, and macrolide antibiotics.
Environmental chemicals-induced hearing loss may be caused by agents (i.e., environmental chemicals) which damage the ear (such as butyl nitrite, mercury or toluene).
Cancer-induced hearing loss may be caused by tumors in the middle ear as well as by other cancers which involve the ear and/or brain.
Surgical-induced hearing loss may occur after otologic or non-otologic surgery; however, the mechanism(s) associated with such hearing loss are not clear.
Radiation-induced hearing loss may be caused by intentional (for example, in radiation therapy) or unintentional exposure to radiation.
Infection-induced hearing loss may be caused by infections involving the inner ear and hearing nerve as well as by infections involving the middle ear. Moreover, there are a number of other types of infections (e.g., mumps, lyme disease, meningitis, herpesvirus infections, fungal infections, bacterial infections, AIDS, and tuberculosis) which may result in hearing loss.
Presbycusis appears to be related, in part, to noise exposure and is characterized by a stiffening of the basilar membrane and deterioration of the hair cells, stria vasularis, ganglion cells, and cochlear nuclei.
Certain drugs (i.e., nicergoline (US Published Application No. 2007/0123555), citalopram (Cruz, et al., Laryngoscope, 2004, 114, 1656-1659), L-carnitine (Derin, et al., Clin. Otolaryngol., 2004, 29, 238-241), and D-methionine (Campbell, et al., Hearing Reasearch, 1996, 102, 90-98)), have been suggested as possible treatments for various types of hearing loss; however, a need exists for pharmaceutical products and improved methods for treatment of hearing loss.
1-Amino-alkylcyclohexanes such as neramexane (also known as 1-amino-1,3,3,5,5-pentamethylcyclohexane) have been found to be useful in the therapy of various diseases especially in certain neurological diseases, including Alzheimer's disease and neuropathic pain. 1-Amino-alkylcyclohexanes such as neramexane are disclosed in detail in U.S. Pat. Nos. 6,034,134 and 6,071,966, the subject matter of which patents is hereby incorporated by reference. It is believed that the therapeutic action of 1-amino-alkylcyclohexanes such as neramexane is related to the inhibition of the effects of excessive glutamate at the N-methyl-D-aspartate (NMDA) receptors of nerve cells, for which reason the compound is also categorized as an NMDA antagonist, or NMDA receptor antagonist. More specifically, neramexane appears to be a low to moderate-affinity, non-competitive NMDA-receptor antagonist believed to selectively block the excitotoxic effects associated with abnormal transmission of glutamate.
U.S. Pat. No. 6,034,134 discloses that 1-amino-alkylcyclohexanes may be useful in the treatment of tinnitus due to their activity as NMDA receptor antagonists.